1. Field of the Invention
The present invention is related to a process for preparing divinylarene dioxides, particularly divinylarene dioxides derived from divinylbenzene. More specifically, the present invention relates to a process for preparing a divinylarene dioxide including reacting (a) at least one divinylarene; and (b) at least one peroxycarboximidic acid.
2. Description of Background and Related Art
In general, epoxidation of olefins can be accomplished by a variety of different methods. For instance, the prior art methods include: (1) reaction of an olefin with hypochlorite to form a chlorohydrin, followed by reaction with a base to form an epoxide; (2) oxidation by peroxy carboxylic acids; (3) oxidation by organic hydroperoxides with a catalyst; (4) oxidation by hydrogen peroxide with a catalyst; or (5) oxidation by other oxidants such as sodium hypochlorite, iodosyl benzene, or peroxycarbonate in the presence of a catalyst.
Epoxidation of olefins by peroxycarboximidic acids is disclosed in U.S. Pat. No. 3,053,856. In the process of U.S. Pat. No. 3,053,856, hydrogen peroxide reacts with a nitrile under controlled pH conditions to form a peroxycarboximidic acid which reacts with an olefin to form an epoxide and an amide. The overall reaction is shown below with acetonitrile and hydrogen peroxide used to make the peroxyacetimidic acid:

M. Worzakowska, J. Appl. Poly. Sci.(2007) vol103, pp462-469, discloses epoxidizing divinylbenzene (DVB) by a method similar to that described in U.S. Pat. No. 3,053,856 using acetonitrile-hydrogen peroxide with magnesium oxide catalyst and greater than a 4-fold molar excess of hydrogen peroxide to olefin. Worzakowska reports a 90 percent (%) degree of epoxidation. In the method of Worzakowska, DVB, acetonitrile, water (pH 10), and MgO are charged into a reactor, warmed to 50° C., whereupon addition of a mixture of 60% hydrogen peroxide and methanol are added slowly over 2 hours, followed by continued heating and stirring for a total of 5 hours. The method used by Worzakowska is disadvantaged in terms of process safety and economics due to the large excess of hydrogen peroxide required. This excess of hydrogen peroxide has to be recovered and reused for Worzakowska's method to be viable on an industrial scale.
U.S. Pat. No. 2,977,374 discloses epoxidizing DVB using peracetic acid in ethyl acetate and reports a divinylbenzene dioxide (DVBDO) yield of 49%. In U.S. Pat. No. 2,977,374, an 81% yield of styrene oxide is reported. Although olefins such as styrene and DVB are structurally similar, epoxidation of these two olefins will not give comparable results, as shown in U.S. Pat. No.2,977,374. Epoxidation using peracetic acid generates acetic acid as a co-product which is known to react with the epoxide product to give a hydroxy ester byproduct, thereby lowering the yield of the epoxide product. In the case of a diolefin, there is twice as great a probability that any given molecule of starting diolefin will form a byproduct as compared to the corresponding monoolefin.
In view of the problems with the known prior art processes, it is desired to provide a process to make a divinylarene dioxide such as DVBDO on an industrial scale which gives good yields of divinylarene dioxide product at the lowest possible oxidant cost.